Gasoline



Patented Nov. 12, 1946 GASOLINE Ernest 'L. Walters, San Francisco, Calif., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application March 6, 1943, g I

Serial No. 478,290

12 Claims. (Cl. 44 14),

This invention relates to gasolines having improved oxidation stability and knock rating.

A principal object is to provide motor fuel of greater stability and decreased age deterioration. Another purpose is to produce aviation gasolines which ar both high in octane rating and low,

in gum forming or precipitating tendencies. Other objectives will be apparent from the following description.

Inmy copending application Serial No. 441,876, filed May 5, 1942, I showed that 2,4-dimethyl-6- tertiary butyl phenol possesses unique and extraordinary inhibitor powers for tetra-alkyl lead fluid as well as for an initially stable gasoline (such as substantially saturate gasolines, for example aviation gasoline, as distinguished from unstable or cracked gasoline), which stable gaso-- line has been rendered unstable by the addition of tetra-alkyl lead.

I have now .found that a small quantity of aniline or an alkyl aniline having not more than 6 carbon atoms in the alkyl radicals, in addition to giving an excellent anti-knock rating, unexpectedly accelerates or increases the inhibiting effect of 2,4-dimethyl-6-tertiary butyl phenol. This is especially true. in initially stable leaded motor fuels such as aviation gasoline in which 2,4-dimethyl-6-tertiary butyl phenol is used with particular effectiveness as an anti-ox dant. However, this cumulative inhibiting effect of anilines and 2,4-dimethyl-6-tertiary butyl phenol may also be observed in normally unstable or cracked gasolines which may or may not contain lead.

Among the many mononuclear aromatic amines applicable to my invention, particular mention may be made of the following: aniline, N-monoand dimethyl or higher alkyl anilines (which may also be substituted in the nucleus), mono-, di-, and trimethyl and higher alkylated anilines (which may also be substituted on the N atom), toluidines, xylidines, cymidine, cumi- 'dine, pseudo cumidine, etc. as well as suitable substituted derivatives. 0bviously, mixtures of aromatic amines, as well as the individual amines may be thus employed. Likewise, aromatic-rich petroleum fractions may be nitrated and reduced to give mixtures such as described in U. S. Patents 1,844,362 and 2,252,099 which may be blended in a motor fuel according to the present invention. These amines by themselves have little if any anti-oxidant effect.

Amounts of aromatic. amines between about 0.25% and 3% are quite effective although higher or lower quantities may be employed. A content break in the induction period does not occur, but

rather the formation of deterioration products proceeds slowly and a visible precipitate forms only after extended aging. This is in marked contrast to the action of most oxidationinhibitors whose efiectiveness is usually terminated quite suddenly at the end' of their period of stabilization with the rapid formation of degradation products in the gasolineand the consequent prompt termination of the usefulness of the motor fuel.

The invention may be further illustrated by reference to tests made with pure xylidine (5-amino- 1,3-dimethyl benzene) in a octane aviation gasoline composed of approximately 45% straight run gasoline, 45% alkylate and 10% cyclopentane and containing 4 cc. of tetraethyl lead fluid per gallon.

Tifmc required h} (inn 5 mg. 0 Ammvc A. s. 'r. M. gum/ 100 ml., hours None 2.33 1% xylirlinc 4,5 2,4-(1 i;ncthyl-6-tcrtiary butyl phenol (l mgJlOO 37 5 ml. 2,4-dimcthyl-fi-tcrtiary butyl phenol (l mgJlOO 100 ml.)+l% xylidinc 78 of less than 7.

7. A gasoline type motor fuel containing about 0.0001-0.1% 0f 2,4-dimethyl 6 tertiary butyl phenol and about .25 to 3% of a mononuclear aromatic amine containing less than '1 carbon atoms in alkyl radicals.

8. A substantially saturate originally stable gasoline-type motor fuel to which has been added tetraalkyl lead to render it potentially unstable,

containing a stabilizing amount of 2,4-dimethyl- I fi-tertiary butyl phenol and a mono-nuclear aromatic amine in which carbon atoms in all alkyl radicals is less than '7.

the total number of- 9. A substantially saturate originally stable gasoline-type motor fuel to which has been added tetraalkyl lead to render it potentially unstable, containing a stabilizing amount of 2,4-dimethyl- 6-tertiary butyl phenol and xylidine.

10. A substantially saturate originally stable gasoline-type motor fuel to which has been added tetraalkyl lead to render it potentially unstable, containing a stabilizing amount of 2,4-dimethylfi-tertiary butyl phenol and toluidine.

11. A substantially saturate originally stable gasoline-type motor fuel to which has been added tetraalkyl lead to render it potentially unstable,

' containing a stabilizing amount of 2,4-dimethyl- G-tertiary butyl phenol and aniline.

12. An improved motor fuel consisting essentially of originally stable gasoline to which has been added suflicient tetra ethyl lead to render it potentially unstable, about 0.0001 to 0.1% w. of 2,4-dlmethyl-6-tertiary butyl phenol and about 0.25 to 3% v. xylidine.

ERNEST L. WALTERS. 

